title: Isotype commitment in the in vivo immune responses. I. Antigen-dependent specific and polyclonal plaque-forming cell responses by B lymphocytes induced to extensive proliferation.
abstract: The random recombination and deletion hypothesis for the control of isotype commitment in antibody responses was directly tested in a serial transfer system in vivo. Normal or hyperimmune spleen cells were used in weekly serial transfers with antigen into irradiated recipients until clonal senescence was observed. Antigen-specific and -nonspecific plaque-forming cells of all isotypes were determined at each transfer time. No major changes in the isotypes of specific antibodies were observed for the whole life-span of the transferred cells (9-10 wk), and no indication was obtained for the accumulation of cells transcribing the most 3' members of the C-gene cluster with sustained proliferation. Rather, the dominant isotypes were found throughout the response to be IgG1, IgG2b, and IgG2a. The results imply isotype-specific regulatory mechanisms in the control of Ig class production. These appear to operate as well in the antigen-nonspecific component of the immune response.
mesh_terms: D000818:Animals; D000917:Antibody Formation; D000941:Antigens / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000637:transplantation; D002455:Cell Division; D002470:Cell Survival; D005786:Gene Expression Regulation; D005802:Genes, MHC Class II; D007114:Immunization; D007126:Immunoglobulin Allotypes / Q000096:biosynthesis*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D011995:Recombination, Genetic; D013154:Spleen / Q000276:immunology
chemical_list: D000941:Antigens; D007126:Immunoglobulin Allotypes